Bacterial Contamination of Platelet Units: A Case Report and Literature Survey With Review of Upcoming American Association of Blood Banks Requirements

Archives of Pathology & Laboratory Medicine, Mar 2004 by Burns, Kathleen H, Werch, Jochewed B

The most common transfusion-associated infectious risk in the United States today is bacterial contamination of platelet components. Bacterial contamination is estimated to occur at an incidence of 1:1000 to 1:3000 in platelet units, with severe episodes estimated to occur in about one sixth of contaminated products. Increased awareness and prompt reaction of the medical team can greatly affect the outcome and save a patient's life. The following case history illustrates this issue. A young woman developed chills and rigors while receiving 1 unit of leuko-reduced apheresis platelets for severe thrombocytopenia. The transfusion was stopped, blood cultures were drawn, and the patient developed clinical signs of sepsis. Cultures of both the platelet unit and the patient's blood revealed coagulasenegative Staphylococcus. Microbial susceptibilities in both samples were identical. Pretransfusion blood cultures taken from the patient earlier that day were negative. The platelet unit had been stored for 5 days. We review this case and the literature describing the persistent problem of platelet unit contamination and at the same time highlight the efforts now directed by the American Association of Blood Banks and College of American Pathologists to address this issue. Although there is no uniform approach to dealing with bacterial contamination of platelets, the American Association of Blood Banks and the College of American Pathologists have promulgated new accreditation requirements in an effort to prevent bacterial sepsis associated with platelet transfusion. A new American Association of Blood Banks standard, which will be effective March 1, 2004, requires a combination of strategies both to limit the initial inoculation of bacteria into the blood component and to detect subsequent growth at room temperature (American Association of Blood Banks Association Bulletin #03-12). The new College of American Pathologists Checklist question, which became effective in December 2003, is a Phase 1 requirement that calls for inspected facilities to have a platelet bacteria detection method in place.

(Arch Pathol Lab Med. 2004;128:279-281)

Platelets are stored at room temperature to maximize their in vivo survival and hemostatic efficacy posttransfusion. ABO-compatible platelets are demanded for the management of thrombocytopenia or platelet dysfunction, and platelet supply is compromised by the regulated short storage period. Although microbial pathogens can grow in red blood cell fractions stored at 40C, the room temperature storage of platelets permits the survival and rapid proliferation of a broader spectrum of bacteria. This limits the shelf life of platelets to 5 days, the shortest period of time that a blood fraction can be kept, and requires continual discard of outdated platelet units. Unfortunately, despite this precaution, the hazards of platelet transfusion still include serious septic reactions. Nearly 9 million platelet units are transfused each year in the United States, and it is estimated that this number includes thousands of contaminated units. Adverse reactions associated with transfusion of contaminated blood products commonly include fever and chills and may never be seriously evaluated. However, bacterial contamination underlies approximately 17% of transfusion-associated deaths, and the risk of septic death is on the order of 200 to 400 times greater than the risk of contracting a virus like human immunodeficiency virus (HIV) or hepatitis C virus (HCV) through transfusion. Of those deaths reported to the US Department of Health and Human Services (Food and Drug Administration) and caused by transfusion of bacterially contaminated blood products, at least half are due to platelet unit contamination.

CASE REPORT

An 18-year-old African American woman with no contributory past medical history presented to the emergency room after 2 days of progressive shortness of breath, joint pain, and petechiae on the lower extremities. She had a pericardial effusion and severe thrombocytopenia (5 � 10^sup 3^/�L). Her vital signs before transfusion were temperature, 101�F; pulse rate, 112/min; blood pressure, 161/81 mm Hg; and respiratory rate, 20/min. Because the patient was febrile, blood cultures were drawn prior to platelet transfusion. She was premedicated with acetaminophen and diphenhydramine hydrochloride. The second apheresis platelet transfusion was begun at 7:00 PM and stopped shortly thereafter, as the patient developed chills and rigors. Vital signs at midnight showed a temperature of 103.7�F, a pulse rate of 137/min, blood pressure of 161/89 mm Hg, and a respiratory rate of 26/min. The next day she was started on an antibiotic regime (cefepime and vancomycin). Blood cultures taken posttransfusion grew coagulase-negative, [beta]-lactamase-positive Staphylococcus, as did the unused portion of the second platelet unit. Pretransfusion cultures were negative for bacterial growth. The patient was transferred to intensive care in respiratory distress; antibiotics were continued, and she ultimately recovered. She was diagnosed with systemic lupus erythematosus, and her presenting conditions improved with prednisone before discharge.